Seasonally Varying Northern Hemisphere Annular Mode

SV-NAM Homepage


( Masayo OGI, Koji YAMAZAKI, and Yoshihiro TACHIBANA )

The SV-NAM index is the standardized score of the leading EOF of the monthly and zonally averaged geopotential height fields poleward of 40N from 1000 hPa to 200 hPa.
The EOF is performed separately for each individual calendar month.
Data to compute the EOF is the NCEP/NCAR reanalysis dataset for 1958 to 2002. For the period prior to 1958, the score is calculated from the projection of monthly anomalies onto the leading EOF pattern.
See Ogi, Yamazaki & Tachibana (2004,JGR) for details.

Horizontal patterns of geopotential height anomalies at 500 hPa regressed on SV-NAM index are shown here (pdf file).

Monthly data for SV-NAM index is here. and here (in Ogi's HP)
Daily index in Tachibana's HP

...
Geopotential height anomalies at 500 hPa associated with SV NAM. C.I.=10m.

(Top):Anomalies in [U] and meridional circulation associated with SV NAM.
(Bottom):Anomalies in [T] and meridional circulation associated with SV NAM.
(Left): winter, (Right) summer

Link to Ogi's Home Page

Link to Tachibana's Home Page

Link to Yamazaki's Home Page

Ogi, M., K. Yamazaki, and Y. Tachibana, The summertime annular mode in the Northern Hemisphere and its linkage to the winter mode.
J. Geophys. Res., 109, D20114, doi:10.1029/2004JD004514, 2004.
[published 28 October 2004]
PDF file for the manuscript
(C)Copyright 2004, American Geophysical Union (AGU).
AGU will not guarantee that the copy provided here is an accurate one published in the Journal.

Related publications by our members.

Ogi, M., Y. Tachibana, and K. Yamazaki, 2003: Impact of the North Atlantic Oscillation (NAO) on the Summertime Atmospheric Circulation. Geophys. Res. Lett., 30(13), 1704, doi:10.1029/2003GL017280. [published 10 July 2003]
(C)Copyright 2003, American Geophysical Union (AGU) pdf file
AGU will not guarantee that the copy provided here is an accurate one published in the Journal.

Ogi, M., K. Yamazaki, and Y. Tachibana, 2003: Solar cycle modelation of the seasonal linkage of the North Atlantic Oscillation (NAO). Geophys. Res. Lett., 30(22), 2170, doi:10.1029/2003GL018545. [published 28 November 2003]
(C)Copyright 2003, American Geophysical Union (AGU) pdf file
AGU will not guarantee that the copy provided here is an accurate one published in the Journal.

Ogi, M., Y. Tachibana, and K. Yamazaki, 2004: The connectivity of the winter North Atlantic Oscillation (NAO) and the summer Okhotsk high. J. Meteor. Soc. Japan, 82, 905-913.
(C)Copyright 2004, Meteorological Society of Japan (MSJ) pdf file

Ogi, M., K. Yamazaki, and Y. Tachibana, 2005: The summer northern annular mode and abnormal summer weather in 2003, Geophys. Res. Lett., 32, L04706, doi:10.1029/2004GL021528. [published 19 February 2005]
(C)Copyright 2005, American Geophysical Union (AGU) pdf file

Nakagawa, K. I., and K. Yamazaki, 2006: What kind of stratospheric sudden warming propagates to the troposphere? Geophys. Res. Lett., 33, L04801, doi:10.1029/2005GL024784. [published 16 February 2006]

Ogi, M., and Y. Tachibana, Influence of the annual Arctic Oscillation on the negative correlation between Okhotsk Sea ice and Amur River discharge, Geophys. Res. Lett., 33, L08709, doi:10.1029/2006GL025838, 2006. [published 26 April 2006]